BLACK water when I drained the block today...

[wca_tim]

Engine is out on the stand, chevy small block, water is black. If it were a car I'd say that had a slight head gasket leak, but am leaning toward galvanic corrosion (black aluminum oxide?). Static compression when checked a few weeks ago was 190 - 195 on every cylinder and I haven't noticed any real loss in performance.

I'm running aluminum exhaust manifolds and intake manifold, and only rarely do I get in brackish in them. Always flush thoroughly when I do. I have stainless risers and aluminum exhaust and so am a little worried about corrosion...

Any thoughts?

 

[mkast]

Re: BLACK water when I drained the block today...

What 's in the coolant passages?
Pull a core plug and do some investigating, dig around the bottom of the passage with a pick, light and mirror. I think there is some "stuff" in there.

 

[wca_tim]

Re: BLACK water when I drained the block today...

no chunks... color is fine like silt almost and there is some that is black and some that is brown... fresh engine build last season (block was tanked, all internals, rods, pistons, crank, as well as heads, manifolds, water pump, etc... - everything - is new as of last season).

It may just be the river dirt and some rust and perhaps aluminum corrosion to go along with it. I've got calls in to see about having exhaust manifolds hard anodized along with the new intake... and for the time being will put it back together with a couple of zinc anodes until I'm sure what the deal it. my battery has been going dead, so I wonder if I had some stray current or a weak ground somewhere that would contribute to making it corrode..